Recognition of the condition in which diseased kidneys are no longer capable of performing their function is a matter of great importance and interest for both physician and surgeon. For this purpose purely clinical evidence is insufficient; nor is it possible to reach a trustworthy conclusion from examination of the urine, or from a study of the bodily metabolism or of the constitution of the blood, while the determination of the latter would, besides, be attended with considerable difficulty. A more practicable and a more satisfactory method of gaining the desired information consists in a determination of the molecular concentration of the blood by ascertaining its freezing-point.
It has been found that the molecular concentration of human blood, as well as the blood of various animal species, is, as represented by the freezing-point, fairly constant under physiologic conditions, being between 0.56 and 0.58 C. lower than that of distilled water.